Holtek HT48R05A-1 Handbook page 3

Special Function Registers ............................................................................................19
Indirect Addressing Register - IAR .........................................................................19
Memory Pointer - MP..............................................................................................19
Accumulator - ACC.................................................................................................20
Program Counter Low Register - PCL ...................................................................20
Look-up Table Registers - TBLP, TBLH .................................................................20
Watchdog Timer Register - WDTS .........................................................................20
Status Register - STATUS ......................................................................................21
Interrupt Control Register - INTC ...........................................................................22
Timer/Event Counter Registers ...............................................................................22
Input/Output Ports and Control Registers ...............................................................22
Input/Output Ports .........................................................................................................23
Pull-high Resistors ..................................................................................................23
Port A Wake-up .......................................................................................................23
I/O Port Control Registers .......................................................................................23
Pin-shared Functions ..............................................................................................24
Programming Considerations .................................................................................26
Timer/Event Counters ....................................................................................................26
Configuring the Timer/Event Counter Input Clock Source ......................................26
Timer Register - TMR ............................................................................................27
Timer Control Register - TMRC..............................................................................27
Configuring the Timer Mode ...................................................................................28
Configuring the Event Counter Mode .....................................................................29
Configuring the Pulse Width Measurement Mode ..................................................29
Programmable Frequency Divider (PFD) and Buzzer Application ..........................30
Prescaler .................................................................................................................31
I/O Interfacing .........................................................................................................31
Programming Considerations .................................................................................31
Interrupts .......................................................................................................................32
Interrupt Register ....................................................................................................32
Interrupt Priority .......................................................................................................33
External Interrupt ....................................................................................................33
Timer/Event Counter Interrupt ................................................................................33
Programming Considerations .................................................................................33
Reset and Initialization ..................................................................................................34
Reset ......................................................................................................................34
Oscillator .......................................................................................................................38
System Clock Configurations .................................................................................38
System Crystal/Ceramic Oscillator .........................................................................38
System RC Oscillator .............................................................................................39
Watchdog Timer Oscillator .....................................................................................39
Power Down Mode and Wake-up .................................................................................39
Power Down Mode .................................................................................................39
Entering the Power Down Mode .............................................................................39
Standby Current Considerations .............................................................................40
Wake-up ..................................................................................................................40
Cost-Effective I/O Type MCU
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